Inworld's new Mutations function enables game creators to dynamically trigger changes to NPC personalities and behavior at runtime.

Character arcs actively enhance the depth and richness of storytelling by showcasing personal growth, transformation, and struggles of characters. In video games, players actively invest themselves in the development and evolution of characters, forging a stronger connection with the game world and developing a deep attachment to their journeys.
In scripted games, characters often follow a ‘flat character arc’ style of storytelling; a predefined storyline and progression, with limited room for players to influence the characters' development. But what if characters could evolve during gameplay?
Inworld's new Mutations function enables game creators to dynamically trigger changes to NPC personalities and behavior at runtime. This feature allows players to witness the transformation and growth of these characters in response to their actions. It creates an immersive and engaging gaming experience where NPCs adapt and respond to the ever-changing game environment, enhancing player engagement and creating memorable gaming experiences.
Mutations is a function within the Inworld Goals and Actions system. Creators can now leverage ‘Actions’ in the YAML to orchestrate any change in character attributes and descriptions when the custom activation conditions are met. The character logic can be input using the fields, which can be configured through client-side Triggers or Intents.
The following types of scenarios can be created using the Mutations function:
- name: new_planet
activation:
intent: ship_docked
actions:
- character_changes:
set_motivation: "{character} wants to establish a base on the unexplored planet they've just landed on"
- name: player_knighted
activation:
trigger: player_knighted
actions:
- character_changes:
set_custom_dialogue_style:
set_adjectives:
- "respectful, loyal, admiring"
set_colloquialism: "phrases for addressing medieval nobility"
set_personality:
aggressive_peaceful: 6
set_mood:
disgust_trust: 8
- name: victim_one_identity
activation:
trigger: victim_one_unlocked
actions:
- character_changes:
enable_common_knowledge:
- "f1603f52-a2ac-4823-8d22-d0641336d1f3"
- name: flaw_exposed
activation:
intent: espionage
actions:
- character_changes:
set_flaws: "{character} starts babbling incoherently if {player} confronts him about the espionage"
- name: status_warrior
activation:
trigger: status_warrior
actions:
- character_changes:
set_profile_variables:
- id: "status_level"
value: "warrior"
set_dialogue_style: VILLAINOUS
set_relationship: ENEMY
Dynamic character evolution transforms how players perceive and engage with NPCs. More dynamic and lifelike characters mean players will develop a deeper sense of connection and investment in your game world as their actions and choices directly impact the people, aliens, or elves they encounter.
Interested in trying Mutations for yourself?